QUAREC ASC
This evacuable reaction chamber was built to study homogeneous gas phase reaction systems, although the design of the experimental set-up is also suitable to investigate incipient aerosol formation.
QUAREC (QUArtz REaCtor) ASC consists of two quartz cylinders (47 cm diameter and 3 m length) connected in the middle by a flange. The reactor is sealed at both ends by enamelled aluminium flanges on which various ports are mounted. The reactor has a total volume of 1.08 m3 and an inner surface of 9.5 m2. The homogeneity of the gas mixtures is achieved with 3 Teflon® fans (magnetic drive coupling) placed on the middle flanges and on the end caps. The reactor body is surrounded by an irradiation system and encased in a box made of high-reflectivity metal sheets.
Its construction is flexible with respect to irradiation capabilities and investigation means. Thus, quartz has a larger transmittance range than borosilicate glass, and installing the lamps required for a certain experimental set-up is not difficult. Similar, the ports on the discs sealing the quartz cylinder and on the middle flange allow for on-line coupling of a large spectrum of analytical instrumentation.
Operation and cleaning of the reaction chamber follow routine schedules. However, observing certain physical limitations, these are suitable to changes as demanded by experimental design.
QUAREC ASC is commonly operated under dry tropospheric likely conditions, namely atmospheric pressure and 298 ± 2 K. A temperature regulating system, to ensure experimental temperatures in the range of 283 – 303 K, will be fully operable end of 2024.
As bath gases, synthetic air or N2 (high purity, Linde) might be used.
The reaction chamber is cleaned after every experiment by evacuating for at least 30 minutes. When the chamber is not in use, the turbo pump is working continuously. Dismantling of the chamber and manually cleaning of the quartz body and the components it contains (White system mirrors, fans, ports and joints, etc.) is performed once a year or often, if the quality of the analytical signals demands it.
The reactor is surrounded by 64 evenly placed connector slots to accommodate lamps with different wavelengths, which can be switched on in pairs, according to the desired type of experiment.
The lamps commonly deployed with QUAREC ASC are: 32 Philips TL05 40 W superactinic fluorescent lamps (300–460 nm, Imax at l ≈ 360 nm) and 32 Philips TUV 40 W low-pressure mercury vapour lamps (max. intensity at 254 nm).
For cleaning purposes, the reactor is served by a double-stage rotary fore pump coupled with a turbopump (Pfeiffer) to ensure a final vacuum of 10-4 mbar.
QUAREC ASC features a White multiple reflexion mirror system, installed on both ends of the quartz cylinder (active path way 484.7 ± 0.8 m) and coupled with a FTIR instrument (Nicolet iS50).
At the QUAREC facility, a choice of on-line (mobile) instrumentation is available which can be coupled to any of the three atmospheric simulation chambers, according to the desired experimental design.